1. Field
Apparatuses and methods consistent with exemplary embodiments relate to an ultrasonic transducer and a method of manufacturing the same.
2. Description of the Related Art
Ultrasonic transducers (e.g., micromachined ultrasonic transducers (MUTs)) convert an electric signal to an ultrasonic signal and vice versa. Ultrasonic transducers may be used, for example, in medical image diagnosis apparatuses, and thus may non-invasively obtain a picture or an image of tissue or an organ of a body. Ultrasonic transducers may be classified into piezoelectric micromachined ultrasonic transducers (pMUTs), capacitive micromachined ultrasonic transducers (cMUTs), and magnetic micromachined ultrasonic transducers (mMUTs), according to the signal converting method. From among these ultrasonic transducers, cMUTs are widely used.
cMUTs transmit and receive ultrasonic waves using a displacement variation of hundreds or thousands of oscillating membranes microprocessed on a silicon wafer. cMUTs may include a silicon wafer that is used in a general semiconductor process, a thin film disposed on the silicon wafer, and a cavity formed between the thin film and the silicon wafer. The silicon wafer, the thin film, and the cavity may form a capacitor. Once alternating current (AC) flows through the capacitor, the thin film begins to oscillate, thereby generating ultrasonic waves. Since cMUTs may transmit and receive ultrasonic waves without a couplant, such as water or oil, due to the thin film, it is easy to use the CMUTs.